import { assert, assertEquals } from "@std/assert";
import { undo } from "@codemirror/commands";
import { getChunks, getOriginalDoc } from "@codemirror/merge";
import { withDom } from "@berry/util/dom.ts";
import type { OpenFile } from "./edit-types.ts";
import { diffEditor } from "./editor.ts";

Deno.test("diff layout changes retain multiline edits, selection, and undo without serializing removed lines", () =>
  withDom(() => {
    const parent = document.createElement("div");
    document.body.append(parent);
    const opened: OpenFile = {
      working: { machine: "local", root: "/repo", vcs: "jj", identity: "change" },
      file: {
        path: "a.txt",
        from: null,
        status: "modified",
        binary: false,
        modes: { old: "100644", new: "100644" },
        hunks: [],
      },
      original: "first\r\nremoved\r\nend",
      content: "first\r\nnew\r\nend",
      version: "version",
    };
    let latest = opened.content;
    const editor = diffEditor(parent, opened, "unified", {
      changed: (content) => latest = content,
      save() {},
      escape() {},
    });
    try {
      const start = editor.view.state.doc.line(2).from;
      editor.view.dispatch({
        changes: { from: start, to: start + 3, insert: "edited\nextra" },
        selection: { anchor: start + 6 },
      });
      assertEquals(latest, "first\r\nedited\r\nextra\r\nend");
      const selection = editor.view.state.selection.main;
      editor.layout("split");
      assertEquals(editor.content(), latest);
      assertEquals(editor.view.state.selection.main, selection);
      assertEquals(
        parent.querySelector('[aria-label="Original a.txt"]')!.getAttribute("contenteditable"),
        "false",
      );
      editor.layout("unified");
      assertEquals(editor.view.state.selection.main, selection);
      assertEquals(getOriginalDoc(editor.view.state).toString(), "first\nremoved\nend");
      undo(editor.view);
      assertEquals(editor.content(), opened.content);
    } finally {
      editor.destroy();
    }
  }));

Deno.test("sparse edits in long files leave unchanged code out of the editor's diff", () =>
  withDom(() => {
    const parent = document.createElement("div");
    document.body.append(parent);
    const unchanged = Array.from(
      { length: 500 },
      (_, i) => `function kept${i}() { return value + ${i}; }\n`,
    ).join("");
    const opened: OpenFile = {
      working: { machine: "local", root: "/repo", vcs: "jj", identity: "change" },
      file: {
        path: "long.ts",
        from: null,
        status: "modified",
        binary: false,
        modes: { old: "100644", new: "100644" },
        hunks: [],
      },
      original: `function unused() { return 0; }\n\n${unchanged}export const label = "old";\n`,
      content: `${unchanged}export const label = "new";\n`,
      version: "version",
    };
    const editor = diffEditor(parent, opened, "unified", {
      changed() {},
      save() {},
      escape() {},
    });
    const check = () => {
      const oldStart = opened.original.indexOf(unchanged);
      const newStart = editor.content().indexOf(unchanged);
      assert(newStart >= 0);
      const chunks = getChunks(editor.view.state)!.chunks;
      assert(chunks.length > 0);
      for (const chunk of chunks) {
        assert(chunk.toA <= oldStart || chunk.fromA >= oldStart + unchanged.length);
        assert(chunk.toB <= newStart || chunk.fromB >= newStart + unchanged.length);
      }
    };
    try {
      check();
      editor.layout("split");
      check();
      const from = editor.view.state.doc.toString().lastIndexOf('"new"');
      editor.view.dispatch({ changes: { from, to: from + 5, insert: '"edited"' } });
      check();
      assertEquals(editor.content(), `${unchanged}export const label = "edited";\n`);
      editor.layout("unified");
      check();
    } finally {
      editor.destroy();
    }
  }));